In systems which allow mobile terminals to provide services by communicating with servers via wireless communication, in zones where radio waves do not reach such mobile terminals sufficiently (i.e., in so-called blind zones), the communication becomes unstable or is sometimes interrupted, so that a situation in which it is difficult to continue the provision of the services sometimes occurs. As one of methods to deal with such a situation, there has been a method in which data assumed to be used by a certain mobile terminal is transferred from a relevant server to the mobile terminal in advance of the time when relevant communication is interrupted (i.e., a prefetched operation is performed).
In Patent Document 1 below, an example of data prefetch systems related to such methods is described. This data prefetch system operates as follows.
First, a use state prediction unit predicts pieces of data which are assumed to be used by a terminal (assumed to be used by a user thereof) in the future on the basis of histories of user actions, a schedule of the day and the like. Next, an allocation method control unit executes scheduling of data prefetch processes on the basis of the prediction result, and costs incurred by cache processes, such as communication charges. Next, the allocation method control unit acquires the pieces of data stored in relevant servers and performs caching into the mobile terminal on the basis of the scheduling result.
Further, in Patent Document 2 below, another example of the related data prefetch systems is described. In this data prefetch system, the increase of entire data-transfer amount is restrained by sorting out and prefetching only pieces of data each having a high possibility of being used (i.e., pieces of data each having a high degree of importance).